The present invention relates to an adjustable support apparatus, and in particular such apparatus which is useful for supporting items such as microphones, speakers, lights and the like.
Conventional vertically adjustable microphone stands typically utilize a rotatable collar which is threadedly secured to the upper portion of one of the telescoping sections. In order to adjust the height of such stands, it is necessary to use both hands to loosen the collar, raise or lower the upper section, and then secure the collar again by rotating it relative to the stand until it is tightened.
There are several disadvantages associated with such conventional apparatus. For example, two hands are required to adjust the height, the adjuster must typically bend over while loosening or tightening the collar (thereby making it difficult to determine the proper vertical adjustment), the collar may become loose when the microphone is rotated relative to the stand, and the like.
U.S. Pat. No. 4,671,479 discloses a portable, collapsible, adjustable support apparatus which overcomes the aforementioned disadvantages of the prior art by allowing a one-handed adjustment. First (outer) and second (inner) tubular members are telescopically connected, with a base member being attached to the lower end of the first tubular member. The second tubular member includes engagement means adapted to releasably engage the interior surface of the first tubular member. Release means carried by the second tubular member may be actuated by one hand to raise or lower the second tubular member with respect to the first tubular member. More particularly, the engagement means adjacent the lower end of the second tubular member comprises a plurality of wing members and an elongated wedge member which is vertically movable between first (lower) and second (upper) positions. Pliable rubber portions of the wing members are adapted to releasably engage the interior surface of the first tubular member when the wedge member is in the second position. The wedge member is biased to the second position in a manner such that the wing members are urged outwardly against the interior surface of the first tubular member.
Despite its advance over the conventional adjustable support apparatus requiring the use of two hands, the patented apparatus has not proven to be entirely satisfactory in use. Due to the nature of the engagement means, the pliable rubber engaging surfaces of the wing members could be worn down by repeated use, thereby rendering insecure the locking of the telescopic orientation of the tubular members and introducing the possibility of an unintended collapse to the fully telescopic orientation. Further, the nature of the engagement between the wing members and the interior surface of the first tubular member precluded easy rotation of the second tubular member (e.g., the article-bearing member) relative to the first tubular member while the tubular members were in the fixed telescopic orientation. Finally, the engagement between the wing members and the interior surface of the first tubular member did not lend itself well to use of a microphone or like article which was connected to the second tubular member by a laterally extending boom arm such that the weight of the microphone or other article was not substantially aligned with the longitudinal axis of the support apparatus (because the pliable rubber portion of one wing member would be forced against the interior surface of the first tubular member with more force than the pliable rubber portion of the other wing member, thereby leading to uneven wearing of the wing members).
A further disadvantage of the patented apparatus arose not out of the engagement means, but rather the elongated connection means which connected the wedge member (of the engagement means) and the release means carried by the second tubular member. Because the elongated connection means provided only a limited throw or vertical movement of the wedge member in response to even full actuation of the release means, a less-than-full actuation of the release means would not necessarily provide sufficient throw to enable adjustment of the telescopic orientation of the tubular members. This could prove especially disadvantageous in a public setting where the performer had other things on his mind than grasping the release mechanism with sufficient force to effect a full activation thereof.
Accordingly, it is an object of the present invention to provide an adjustable support apparatus wherein in a preferred embodiment the engagement means is formed entirely of metal so that the components thereof do not wear out.
Another object is to provide such an apparatus wherein in a preferred embodiment the engagement means permits relative rotation of the tubular members while maintaining the fixed telescopic orientation of the tubular members.
Still another object is to provide such an apparatus wherein in a preferred embodiment the engagement means precludes further telescopic action of the tubular members, yet allows further untelescoping action of the tubular members without activation of the release means.
A further object is to provide such an apparatus wherein in a preferred embodiment the engagement means is well adapted for use of the apparatus with a boom arm.
It is also an object of the present invention to provide such an apparatus wherein in a preferred embodiment the elongated connection means provides more throw upon actuation of a release member so that even a less-than-complete activation of the release means is sufficient to release the fixed telescopic orientation of the tubular members.
It is another object to provide such an apparatus which is simple and inexpensive to manufacture, use and maintain.
It has now been found that the above and related objects of the present invention are obtained in an adjustable support apparatus comprising a first (e.g., outer) elongated tubular member having upper and lower ends, and a second (e.g., inner) elongated tubular member slidably received within the upper end of the first tubular member and defining a plurality of circumferentially spaced apertures therethrough. Support means is secured to the lower end of the first tubular member. Engagement means, carried by the second tubular member for releasably engaging the interior surface of the first tubular member, includes an elongated wedge member movable between first (e.g., upper) and second (e.g., lower) positions, and a plurality of substantially rigid ball bearings rotatably seated in respective ones of the apertures in the second tubular member. The ball bearings are dimensioned to releasably engage the interior surface of the first tubular member against relative longitudinal movement between the first and second tubular members in a given direction when the wedge member is in the second position and to enable such relative longitudinal movement when the wedge member is in the first position. Biasing means bias the wedge member to the second position, thereby to normally fix or lock the relative telescopic orientation of the tubular members. Actuatable release means is carried by the second tubular member, and elongated connection means connect the wedge member and the release means such that actuation of the release means moves the wedge member longitudinally within the second tubular member from the second position to the first position.
Preferably the tubular members, the wedge member and the ball bearings are steel.
In a preferred embodiment, the ball bearings are longitudinally rotatable in a given direction (e.g., to collapse the telescopic orientation of the tubular members) only when the wedge member is in the first position, and are not longitudinally rotatable in the given direction when the wedge member is in the second position. The ball bearings are longitudinally rotatable in a direction opposite the given direction (e.g., to extend the telescopic orientation) even when the wedge member is in the second position. The ball bearings are horizontally rotatable regardless of the position of the wedge memberxe2x80x94that is, both when the wedge member is in the first position and when the wedge member is in the second position.
In another preferred embodiment, there are three ball bearings, generally equidistantly spaced apart about a circumference of the second tubular member. The ball bearings are preferably in direct physical contact with the interior surface of the first tubular member only when the wedge member is in the second position. The first and second tubular members are generally vertically extending, and the ball bearings extend through their respective apertures with their respective centers of gravity intermediate the wedge member and their respective apertures such that the ball bearings are biased by gravity for movement towards the wedge member and away from the interior surface of the first tubular member.